Methods of Making and/or Filling Reclosable Bags

ABSTRACT

Methods of forming and/or filling recloseable bags are disclosed. In some embodiments, the methods include attaching a bag closure strip along one longitudinal edge of a length of bag film, and forming from the length of bag film, a bag having an open end, two broad, opposing faces and a flap. In certain embodiments, the flap is attached to an edge of one of the broad faces along the open end and extending between sealed edges of the bag.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.10/662,266, filed Sep. 15, 2003, which is a continuation ofPCT/US02/08055, filed Mar. 15, 2002, which claims priority to U.S.Provisional Patent Application Ser. No. 60/276,567, filed Mar. 15, 2001,which are incorporated by reference herein.

TECHNICAL FIELD

This invention relates generally to reclosable bags, and to methods ofmaking and/or filling such bags.

BACKGROUND

Convenience packaging, particularly for foodstuffs and bulk materials,frequently involves the use of bags or pouches. These bags can beadvantageously constructed with side or bottom gussets to make them ableto be set upright on a horizontal supporting surface, for filling,display or storage. It is common to refer to bags with bottom expansionpanels and sealed side and top edges as ‘pouches’.

More recently, bags have been produced with expansion panels at both topand bottom, and vertical side seals. Examples of these bags are marketedunder the trade name “Flex-Can”, for example, and are known for theirability to be conveniently stacked one on top of another, like cans.Both the top and bottom panels of these bags expand substantially andsimultaneously as the bags are filled, such that the sides of the bagseparate at both top and bottom, in some cases remaining generallyparallel and vertical. As filled, the bag and its contents can exhibitsignificant structural stability, enabling stacking and convenienthandling, with very little head space above the contents.

SUMMARY

We have realized that it is possible to equip a gusseted bag with areclosable seal adjacent its gusset and have the closure functiondespite the expansion and contraction of the gusset.

The invention features a reclosable, gusseted bag, having an openingdefined adjacent an expansion gusset.

According to one aspect of the invention, a gusseted bag has a body withopposing broad face panels defining a volume therebetween for holding aquantity of contents, an end of the body forming an expandable gussetbetween the broad face panels, and a reclosable bag closure between theexpandable gusset and a corresponding one of the adjacent edge regionsof one of the broad face panels, such that when the closure is opened abag opening is formed between the expandable gusset and said one of thebroad face panels of the bag, to access the bag contents.

In some embodiments, the body has two opposing gussets between the broadface panels on opposite ends of the bag, the bag closure being disposedadjacent one of the gussets. The opposing gussets may be disposed at topand bottom ends of the bag, for example, with the bag constructed torest on its bottom end when filled. Or the bag may be constructed torest on a bottom end when filled, with the two opposing gussets disposedalong opposite vertical sides of the bag, as another example.

In some preferred cases, the gusset and closure are disposed at a topend of the bag with the bag standing on its bottom end. In otherpreferred cases, the gusset and closure are disposed along a verticalside edge of the bag with the bag standing on its bottom end.

In preferred constructions, the bag closure comprises a mechanical touchfastener. In some cases, other closure technologies may be employed,however, such as adhesives. The presently preferred bag closure haselongated, mating bands of hooks, hook-engageable fibers, and a unitarystrip-form base along which the mating bands extend in parallel. Thebase may define a frangible burst membrane between the mating bands,with the membrane arranged to be breached to gain initial access to thebag contents. For some applications, the burst membrane is disposedinboard of the mating bands. To form an advantageous anti-peel flap, forexample, one longitudinal side of the closure may be attached to the bagbody only outboard of the mating bands. That one longitudinal side ofthe closure may be disposed adjacent the outer broad face panel of thebag, with an opposite longitudinal side of the closure being secured tothe gusset.

According to another aspect of the invention, a open bag suitable forfilling with contents and sealing after filling is provided. The bagincludes a body having an open end, two opposing, broad face panelsdefining a volume therebetween for holding a quantity of contents, and aflap attached to one of the broad face panels along the open end, theflap having an inwardly-facing fold for forming an expandable gussetbetween the broad face panels after the open end is sealed. The bag alsoincludes a reclosable bag closure secured to a free edge of the flap anddefining one side of a fill opening at the open end of the bag.

In some embodiments, the bag closure comprises two separate closurestrips. One of the strips is secured to the free edge of the flap, andthe other of the strips is secured to a free edge of an opposing one ofthe face panels, the two strips together forming an overlapping touchclosure and defining the fill opening therebetween.

In some cases the bag body includes two opposing weld flanges outboardof the bag closure and exposed to be sealed together after filling. Oneof the weld flanges extends along the free edge of the flap and theother weld flange extends along a free edge of one of the face panels.The bag body can be provided with a frangible tear line along an inboardedge of at least one of the weld flanges, for tearing the weld flangesfrom the bag to access the contents after filling, for example.

For some applications, the bag also has a wicket extension along a freeedge of one of the face panels outboard of the closure, the wicketextension defining at least one hole therethrough.

In some embodiments, the bag closure comprises a unitary, folded stripcarrying opposing bands of mating touch fastener elements on a frontface thereof, a back face of the folded closure strip defining said oneof the fill opening.

The flap extends between sealed edges of the bag in some applications,to form a full-length gusset. The bag closure may also extend betweenthe sealed edges of the bag.

The bag body also forms an expandable gusset on a side of the bagopposite the flap and bag closure, in some embodiments. In some cases,the bag is constructed to rest on a bottom end thereof when filled, withthe flap and closure disposed at a top end of the bag. In other cases,the bag is constructed to rest on a bottom end thereof when filled, withthe flap and closure disposed along a vertical side edge of the bag withthe bag standing on its bottom end.

According to another aspect of the invention, a method of formingfillable, reclosable bags is provided. The method includes attaching abag closure strip along one longitudinal edge of a length of bag film,and forming from at least the length of bag film a bag having an openend, two broad, opposing faces and a flap with an inwardly-extendingfold. The flap is attached to an edge of one of the broad faces alongthe open end and extending between sealed edges of the bag, with theopen end of the bag defining a fill opening between the closure stripand the other of the broad faces of the bag.

In some embodiments, the closure strip comprises an elongated strip-formbase with two spaced-apart, parallel, mating bands of fastener elementsdisposed on a common face of the base. The base is folded along itslength between the bands of fastener elements to maintain the fastenerelements in engagement while the bag is being formed. One of the matingbands of fastener elements may include hooks, for example, with theother of the mating bands of fastener elements including hook-engageablefibers. In some cases, mutually engaging arrays of headed projectionsmay be employed for the two bands of fastener elements. The band withfibers may include a non-woven web of fiber.

In some cases, forming the bag includes folding the length of bag filmto form both broad face panels and the flap.

Preferably, the bag is formed after the closure strip is attached to thebag film. However, the closure strip may alternatively be attached afteror during bag formation.

In some preferred constructions, the closure strip extends across thebag between the sealed edges of the bag.

Forming the bag includes, in some embodiments, cutting the length offilm and the bag closure strip to selected lengths after the bag closurestrip is attached, and sealing cut ends of the film and closure strip toform the sealed edges of the bag.

According to another aspect of the invention, a method of filling andsealing a reclosable bag is provided. The method includes providing abag with a body having an open end, two opposing, broad face panelsdefining a volume therebetween for holding a quantity of contents, and aflap attached to one of the broad face panels along the open end, theflap having an inwardly-facing fold for forming an expandable gussetbetween the broad face panels after the open end is sealed, and areclosable bag closure secured to a free edge of the flap and having anexposed side defining one side of a fill opening at the open end of thebag; filling the bag with contents through the fill opening; and sealingthe exposed side of the closure strip to the other of the broad facepanels of the bag, to permanently close the fill opening.

According to yet another aspect of the invention, a method of forming,filling and sealing reclosable bags is provided. The method includesattaching a bag closure strip along one longitudinal edge of a length ofbag film; forming from the length of bag film a bag having, two broad,opposing faces and an expandable gusset between the broad faces adjacentthe closure strip; filling the bag with a quantity of contents; andforming a seal along an edge of the bag between the broad faces andcrossing the closure strip at one end of the expandable gusset, to sealthe filled bag. This method is preferably performed in a verticalorientation.

The closure strip is preferably constructed to be folded along a regionbetween the bands of fastener elements and loops to place these bands inreleasable engagement. Preferably, the fastener elements are integrallymolded with resin of the substrate.

In some embodiments, the loop strip comprises a non-woven web ofentangled fibers forming the loops and having a basis weight of lessthan about 4 ounces per square yard (preferably, less than about 2ounces per square yard). In some cases, the non-woven web comprises aneedled web in a stretched condition.

In some presently preferred embodiments, the substrate defines a grooveextending longitudinally along the length of the closure strip betweenthe band of loops and the band of fastener elements. This groove ispreferably lengthwise continuous and defined by molded surfaces in thefront face of the substrate.

The back face of the substrate is preferably void of fastener elementsand loops, for permanently adhering the substrate to the sides of thebag. Regions of the back face may be covered with a layer of adhesivefor permanently attaching the closure strip to opposite sides of a bag,or comprise exposed resin of the substrate, for permanently welding theclosure strip to opposite sides of a bag formed of a compatiblematerial.

In some embodiments of the bag, the closure strip of the bag includes apeelable adhesive seal for resealing the bag after initial opening. Insome cases, this peelable seal also functions to secure the open end ofthe bag against inadvertent opening.

In some embodiments, the substrate of the closure strip is permanentlyaffixed to the side wall of the bag body with adhesive. In some otherembodiments, the substrate of the closure strip is welded to the sidewalls of the bag body. The substrate of the closure strip and the sidewalls of the bag body may both be formed of polyethylene, for instance.

The bag of the invention is constructed both for ready reclosure and forexpansion, obtaining many of the benefits of expandable gusset bags(such as the ability to stand unsupported during storage and display,and to adapt to various fill levels) while also providing for convenient(in some cases, one-hand) reclosure. The mating closure strip bands canbe made relatively wide, for easy alignment despite the conformance ofthe adjacent, expandable gusset. The closure can be placed inside thebag, attached directly to the expansion gusset panel, without requiringadditional flaps. The closure can incorporate hook and loop engagementto provide necessary ventilation for some applications. Such hook andloop closures are also able to accommodate a fair amount of dirt ordebris without losing their function as closures, making bags of thisconstruction particularly applicable for containing granular or powdersubstances. In addition, the natural porosity of hook and loop closurescan provide some degree of filtering of airborne dust. Such a ventilatedclosure can be particularly desirable in cargo containers of airplanesin order to accommodate pressure changes, and, by its venting action,may help to avoid moisture buildup to keep produce and other such itemsfresh. The closure can be readily provided with a central burst membraneto maintain an air-tight seal until the bag is initially opened.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of an empty, open bag.

FIG. 2 is a cross-sectional view of the bag, taken along line 2-2 inFIG. 1.

FIG. 3 shows the bag after filling and sealing.

FIG. 4 shows the bag after initial opening.

FIG. 5 shows such a bag after reclosing, and filled to a greater extent.

FIG. 6 is an enlarged perspective view of the closure strip, laid flat.

FIG. 7 is a perspective view of a filled, sealed bag with a sideclosure.

FIG. 8 is a cross-sectional view, taken along line 8-8 in FIG. 7.

FIG. 9 shows the bag of FIG. 7 after initial opening.

FIG. 10 illustrates pouring contents of the bag of FIG. 7 through theopen side closure.

FIG. 11 shows a bag with an upper expansion gusset that extends over oneupper edge of the bag.

FIG. 12 illustrates a method and apparatus for forming bags.

FIGS. 13-15 are cross-sectional views, taken along lines 13-13, 14-14and 15-15, respectively, in FIG. 12.

FIG. 16 is a cross-sectional view of a folded bag closure strip.

FIG. 17 illustrates a method and apparatus for filling and sealing bags.

FIG. 18 is a cut-away view through an open, gusseted end of a bag havinga two-part closure and a wicket extension.

FIG. 19 shows a vertical form, fill and seal method and apparatus.

FIG. 20 is a cross-sectional view, taken along line 20-20 in FIG. 19.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The disposable, reclosable bag 10 of FIG. 1 has two broad face panels(front panel 12 is fully visible in this view, with only the upper edgeportion of rear panel 16 in view) formed of a single, folded sheet ofpolyethylene film sealed along side edges 14. Bag 10 is suitable forpackaging bulk granular or powdered products, such as consumablefoodstuffs, animal feed, fertilizers, cleaners and the like, for retailsale.

Referring also to FIG. 2, bag 10 is formed to have a bottom gusset 18folded inwardly from the bottom edges of front and rear panels 12, 16and extending across the full length of the bag between side seals 14.The upper edge of front face 12 is folded over twice to form an inwardlyextending top gusset 20. Thus, in this embodiment, a single continuoussheet of bag film is longitudinally folded along five parallel linescorresponding to corners 22, 24, 26, 28 and 30. To help maintain thesharpness of folds 22, 26 and 28, these folds are creased and may evenbe set by thermal sealing or other means. Gusset folds 24 and 30 are notcreased in this example, but can be to enable pre-made bags to be foldedflat.

A reclosable closure strip 32 is attached along the free edge of uppergusset flap 20, such as by continuous thermal welds along two spacedapart, longitudinal regions 34 and 36. Adhesives or other attachmentmeans may also be employed. The closure strip is folded along its centerbetween mating bands of hooks and loops, with the hooks and loopsinitially engaged to hold the closure in its folded state before the bagis filled. Thus, a fill opening 38 is defined between the exposed faceof closure strip 32 and the inner surface of back face panel 16. Theclosure strip and fill opening 38 extend across the length of the bagbetween the side seals, where the closure strip is sealed between thefront and back face panels.

Once the bag has been filled with desired contents (FIG. 3), the outer,free edge of closure strip 32 is sealed to back face panel 16 across theentire length of the bag, forming seal 40 that seals the bag forstorage, shipment and retail display. As the bag is filled, upper andlower expansion gussets 18 and 20 expand, such that the central verticalcross-section of the bag has a generally trapezoidal structure, and theinterior volume of the bag has swelled to accommodate the contents. Insome cases (see also FIG. 5, for example), upper gusset 20 expandssubstantially as much as does bottom gusset 18, such that front and rearface panels 12 and 16 remain generally vertical and parallel. Theexpanded bottom gusset 18 forms a stable base upon which the filled bagmay be readily balanced, and by also expanding upper gusset 20, the sidepanels of the bag bow outward with enhanced structural stiffness alongthe entire height of the bag, for supporting loads from above. Withfiner-grained contents (such as bird seed, for example), much of theload-supporting ability is provided by the constrained contentsthemselves, with the upper and lower gussets enabling the bag to conformto a more block-like structure under the pressure of the weight of thecontents. This bag structure is also suitable for containing liquids,although for many such applications a non-venting closure means will bedesired, either by providing the touch fastener closure with anauxiliary seal or by employing a cohesive closure. In general, face-typeclosure means are preferred for ease of closure with little alignment,but for some applications some types of rib and groove closures, such asself-aligning or multi-rib constructions, for example, may also beemployed adjacent a gusset.

To initially open the bag (FIG. 4), the gusset side of closure strip 32and the upper edge of back panel 16 are grasped in separate hands, andpulled laterally away from each other to burst through the longitudinalfrangible region running along the central portion of closure strip 32between the mating fastener bands and form an access opening 43 alongthe upper end of the bag between the two sides of the closure strip.

Advantageously, bag 10 can be reclosed between uses, such as forpost-sale storage. To reclose the bag, one need only bring the exposedfaces of closure strip 32 back into facial contact to engage the matingfastener bands. Although it might be expected that the tension inadjacent gusset 20 and the resulting non-parallelism of the twoseparated sides of the closure strip would make reclosure difficult, wehave found that with a facial contact closure the two sides of theclosure can be readily brought into useful engagement because only veryminimal alignment and contact pressure is required. The bag may bereclosed and reopened a fair number of times to regain access to the bagcontents. Furthermore, with hook-and-loop closure technology theonce-opened closure provides an integral air and gas vent, such as isknown to be useful for vegetables and certain other perishable bagcontents.

By sending one side of closure strip 32 only along an outer edge region40, the lower width of the closed closure strip is able to flex awayfrom the adjacent side 16 of the bag, as shown in FIG. 5. Theflexibility of the thin resin base of the closure strip 32 also enhancesits ability to align the mated fastener bands with the direction of anyseparating load applied to the closure 32 by tension in the adjacentgusset 20, thus tending to develop shear loads across the mated fastenerbands rather than peel forces that would more readily lead toinadvertent opening at higher fill levels.

Referring now to FIG. 6, lengthwise-continuous closure strip 32 consistsof a thin, sheet-form substrate 42 (of polyethylene, for example) withlengthwise-continuous, parallel bands 44 and 46 of loops and fastenerelements, respectively, on its front face 48. Bands 44 and 46 areequally spaced from a central groove 50 of the closure strip, such thatwhen the strip is folded longitudinally at groove 50 to cover front face48, the fastener elements of band 46 engage and retain the loops of band44 to form a releasable fastening. Preferably, the thickness of thesubstrate of the closure strip is about the same as the thickness of thematerial of the bag body, in the range of 0.002 to 0.005 inch. Thefastener elements 52 of band 46 are integrally molded with and extendfrom front face 48. In this embodiment, these fastener elements are inthe form of J-hooks that extend, in rows, along the length of theclosure strip. Some of the J-hooks face in opposite directions along thestrip. Other fastener element shapes may also be employed, includingthose that overhang the substrate 42 in a widthwise direction. Asuitable fastener element shape is the CFM29 hook shape (of about 0.015inch in height), available in various products sold by Velcro USA inManchester, N.H.

Band 44 of loops consists of a preformed, non-woven web of polymerfibers, which may include a stabilizing binder, and which are bonded tofront face 48 of substrate 42 at various points across the width andlength of the web. Suitable loop materials include those disclosed inU.S. Pat. Nos. 6,342,285 and 6,329,016, the entire disclosures of whichare hereby incorporated by reference as if fully set forth. Other usefulloop materials include some low cost knits, such as ACRI IndustrialTermofijado Knit Loop 4211A99999, available from Tybor S.A. of Girona,Spain.

Closure strip 32 may be produced by the method disclosed in U.S. Pat.No. 6,202,260, and may incorporate other features disclosed in saidpatent, the entire disclosure of which is also hereby incorporated byreference as if fully set forth. Some suitable methods also employfeatures of the nip-molding and in-situ laminating concepts disclosed inU.S. Pat. Nos. 4,794,028 and 5,260,015, the details of both of which arealso incorporated herein by reference.

Closure strip 32 has an overall width of about 2.5 inches (64millimeters) and a nominal thickness of about 0.004 inch (0.1millimeter). Loop and hook bands 44, 46 each have a width of about 0.75inch (19 millimeters). In another preferred embodiment they have widthsof about 0.5 inch (12.5 millimeters), as selected for desired peelresistance. Groove 50 is 0.002 inch (0.05 millimeter) deep and extendsover a width of about 0.125 inch (3.2 millimeter). Thus, at groove 50the closure has a reduced thickness of only about 0.002 inch (0.05millimeter). On either side of groove 50, tear-limiting ribs 52 riseanother 0.002 inch (0.05 millimeter) from the nominal surface of theclosure base to resist propagation of tears from groove 50 into eitherof the fastener bands. Unitarily molded rip-stop features (not shown)may also be included on either side of groove 514 throughout the area ofthe closure separating the hook and loop bands to help resist tearpropagation. The remaining width of the closure strip forms a flange 54outboard of the band 44 of loops, and a narrower flange 56 outboard theband 46 of fastener elements, for welding or otherwise attaching theclosure strip to the bag material.

Although the illustrated, preferred embodiments employ hook-and-loopfastening means, other face-contact closures that do not require precisefeature alignment are also suitable, such as peelable adhesives,inter-engaging arrays of mushroom-type structures that are engageable inseveral relative positions, and other similar closure means.

Referring next to FIGS. 7-10, another bag 60 has two opposing sideexpansion gussets 62 (one hidden from view) and a bottom expansiongusset. Bags of such overall structure may be formed by any of a numberof known methods, such as by welding together individual panels orgroups of panels along various side, top and/or bottom edge seals. Theillustrated bag has a vertical side seal 64 joining one of the sidegussets 62 to face panel 66. Extending from the upper edge 68 of bag 60only partially along seam 64 is a reclosable closure strip 32incorporated into seam 64. Along the length of closure strip 32, theadjacent side gusset 62 is sealed to one outer side of the foldedclosure strip, with face panel 66 sealed to the other outer side of thefolded closure strip (see FIG. 8). In this case, both sides of theclosure strip are secured by welds over a relatively wide width behindthe fastener bands. One end of the closure strip is sealed at the upperedge 68 of the bag, and the other end 70 of the closure strip is sealedwithin side seal 64, such that the filled bag is initially sealed fortransport and retail display.

After sale, the closure strip can be pulled open, as shown in FIG. 9, toburst through the inner membrane of the closure strip and open the bag.Once open, the location of the closure strip along the upper verticaledge of the bag is useful for pouring out the contents of the bag indesired amounts. The upper corner 72 of the opposing side wall gussetforms a convenient handle for inserting one or more fingers to help liftand tilt the bag for pouring, with perhaps another hand grasping thebottom gusset panel edge 74. The weight of the product during pouringcan act to expand the side gusset to minimize trapping product behindthe gusset. After use, the user need only squeeze the side opening ofthe bag closed to re-engage closure 32 for post-use storage. As in theembodiment of FIGS. 1-5, the closure is relatively easy to manipulateand re-engage despite the existence of the adjacent expansion gusset.

Referring now to FIG. 11, bag 80 is equipped with a top expansion gusset82 that extends from upper corner 28 of face panel 12 over the upperedge of face panel 16, and is secured to the outer face of the bag asshown. In this instance, the reclosable closure 84 is in the form of twoseparate strips, one carrying a band of hooks and the other a matingband of loops, such that the closure itself performs no pre-entry sealfunction. Instead, upper gusset 82 is secured to the upper edge of facepanel 16 by a reclosable, pressure-sensitive seal 86 to help preservecontent freshness even after the initial opening of the bag.

Referring now to FIG. 12, bags 10 are formed from a continuous tube 102of bag film from roll 100. Film 102 is pre-folded to have twolongitudinal, folded gussets. Alternatively, the bag-forming process canbegin with a flat sheet of bag film that is then folded around a V-boardwith side gusseters. One edge of the tube, adjacent one of the twogussets, is slit by blade 104 to form a slit tube (FIG. 13). Next, acontinuous closure strip 32 is introduced into the slit around angledbar 106 (FIG. 14), with the longer side of the strip aligned with theouter edge 108 of the tube and the shorter side of the strip alignedwith the inner edge 110 of the tube adjacent the gusset. Next, theclosure strip 32 and slit tube 102 are passed between two nip rollers112 (only one shown) to maintain alignment of the bag film and closurestrip until sealing. The closure strip and bag film are then passedthrough a sealing station 114 where a stationary anvil 116 slides alongthe adjacent gusset, providing a support surface for heated sealing shoe118. Shoe 118 engages the outer surface of the bag film opposite theclosure strip along two parallel regions. Heat from the shoe isconducted through the bag film and closure strip to heat seal the backside of the closure strip to the layer of bag film against anvil 116, toform permanent seals 120 that secure one side of the closure strip tothe bag film, with the other side of the closure strip remainingunattached to the outer edge of the bag film tube.

Referring also to FIG. 16, longitudinal zones of closure 32 are coatedwith an anti-weld coating 122, such as a flexographic overprint thatfunctions to resist sealing adjacent surfaces together in such coatedzones as the closure strip and bag film pass through sealing station114. Suitable coatings include Matte Imprintable Overprint No.AWX5-92105-401, available from Arcargraphics of West Chicago, Ill. Thecoated anti-weld zones may be ⅛ inch to 3/16 inch (3 to 5 millimeters)in width, with a nominal coating thickness of 0.001 inch (0.025millimeter), for example.

Still referring to FIG. 12, the closure strip and bag film next passbetween an opposing pair of transverse sealing bars 124 (again, only oneis shown) that repeatedly come together to seal the bag film togetherunder heat and pressure to form transverse seals 126 connecting adjacentbags 128. The series of connected bags is then spooled on roll 130 forlater filling and sealing. Alternatively, sealing bars 124 may beadapted to both seal the bag film and separate the tube into individualbags that can be stacked or wicketed. Also, instead of spooling thebags, the series of connected bags can immediately enter filling andsealing stations to produce individual, filled bags.

Referring now to FIG. 17, a roll 130 of seriatim bags is unspooled intoa filling and sealing machine 132. The bag film and attached closurestrip are severed within each transverse seal 126 by cutting bar 134 toseparate the individual bags 128. The bags are each held by clamps 136that move along track 138 to transport the empty bags to filling station140, where they are filled with a selected quantity of contentsdispensed through chute 142. As they approach the filling station, thedistance between the two clamps 136 holding each bag is reduced to helpenable the opening of the upper end of the bag for filling. Duringfilling, the lower end of the filling bag is allowed to rest at leastpartially on an indexed conveyer 144. Next, the filled bag moves onconveyer 144 to a top sealing station 146 where the two clamps 136holding the upper corners of the bag within the side seals 126 are movedapart from each other to apply tension along the bag opening as aheated, horizontal sealing bar 148 comes down and engages the upperedges of the closure strip and bag film to seal the bag.

FIG. 18 shows a closure structure for bags that are to be filled throughthe closure, rather than between the closure and bag film. Closure 150consists of two separate strips, a hook strip 152 and a loop strip 154.The two strips may be produced as a single closure strip andsubsequently split into the two strips, if desired. Hook strip 152 isbonded to the bag film along its two edges by heat seals 120. Loop strip154 is only attached along its outer edge by a single continuous heatseal 120, leaving the edge of the loop strip facing into the bag tubefree as shown. The hook and loop strips are aligned with each other suchthat their mating arrays of loops and hooks will engage under lightpressure to reclose the bags formed of this precursor bag film andclosure assembly. The outer edge the bag film has a wicket extension 156of perhaps 1.5 to 2.0 inches (37 to 50 millimeters) in width and joinedto the rest of the bag film along a series of perforations 158.Extension 156 defines a series of through holes 160 for engagement bywickets. In some cases, holes 160 are equally spaced along the bag filmtube for engagement by a tractor wheel during processing. Perforations158 enable the extension and its wicket holes to be severed from therest of the bag film after processing. Adjacent extension 156 is a weldflange 162 outboard of closure 150 and of a width sufficient for sealingthe two outer edges of the bag film together. Another series 164 ofperforations or a weakened tear line may be included to enable thesealed weld flanges 162 to be torn from the rest of the bag film toaccess closure 152 after retail sale, for initial opening, so as toprovide the bag with a tamper-evident tear strip.

FIGS. 19 and 20 illustrate a vertical form-and-fill operation in which afolded continuous length of closure strip 32 is introduced between thefacing edges of bag film 166 advanced about a forming collar 168 onto afill tube 170. As the closure strip and bag film edges are sealedbetween seal bars 172, two gusset wheels 174 direct the bag film intotwo opposing grooves 176 in opposite sides of the fill tube, one of thegrooves and gusset wheels located adjacent the seal flange containingthe closure strip. Immediately below the lower end 178 of the fill tube,twin lateral sealing bars 180 come together at fixed time/lengthintervals to seal across, and cut through, the bag film and closurestrip to form individual, sealed, filled bags. As bars 180 come togetherthey secure the gusset folds created by wheels 174 at the top of afilled bag below bars 180, and secure the bottom ends of the gussetfolds of the next bag to be filled, above bars 180. In some cases, bars180 form two lateral seals and incorporate a cutting bar to cut throughthe bag film between the seals.

Wicketed, gusseted bags having the reclosable closure as shown in FIG.18 can also be filled in a horizontal filling process (not shown), suchas one in which the contents are inserted through a spring-loaded duckbill insertion tube. Such bags can be received as a wicketed stack asknown, for example, in the packaging of bread and the like. The top bagof the stack is air inflated, and the force of over-inserting theproduct rips the bag from the wicket. In some cases, the product may beinserted without tearing the bag from the wicket, the closure can beclosed and the weld flanges 162 sealed together to seal the bag whilethe bag is yet on the wicket. Then, the wicket extension 156 can be tornfrom the bag along line 158, or can be slit from the bag during sealing.Such a filling method and bag structure is useful for packaging frozenfood items, such as fish sticks and waffles and the like, as the hookand loop bag closure functions well as a repeat closure under very coldconditions as are found in freezers (where some adhesives exhibit somedeterioration of function), and also continue to close through crumbsand other debris generated by repeated access to such contents.

The gusseted, reclosable bags discussed above can also be employed forpackaging items in trays, such as coffee cakes and the like that arecommonly packaged in boxes. The width of the bag between the side sealsshould be sufficient to enable the side seals to be displaced toward oneanother as the opening is extended to full height over a widthsufficient to receive the product. After filling and sealing, the endgussets of such bags help to provide a box-like appearance for retaildisplay. The aluminum trays in which such cakes are baked could haveextended side panels to enable such packages to be stacked withoutdamaging the goods, for example.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A method of forming fillable, reclosable bags, the method comprisingattaching a bag closure strip along one longitudinal edge of a length ofbag film; and forming from the length of bag film, a bag having an openend, two broad, opposing faces, and a flap with an inwardly-extendingfold, the flap attached to an edge of one of the broad faces along theopen end and extending between sealed edges of the bag, the open end ofthe bag defining a fill opening between the closure strip and the otherof the broad faces of the bag.
 2. The method of claim 1 wherein theclosure strip comprises an elongated strip-form base with twospaced-apart, parallel, mating bands of fastener elements disposed on acommon face of the base, the base folded along its length between thebands of fastener elements to maintain the fastener elements inengagement while the bag is being formed.
 3. The method of claim 2wherein one of the mating bands of fastener elements comprises hooks,and the other of the mating bands of fastener elements compriseshook-engageable fibers.
 4. The method of claim 3 wherein the band withfibers comprises a non-woven web of fiber.
 5. The method of claim 1wherein forming the bag comprises folding the length of bag film to formboth broad face panels and the flap.
 6. The method of claim 1 whereinthe bag is formed after the closure strip is attached to the bag film.7. The method of claim 1 wherein the closure strip extends across thebag between the sealed edges of the bag.
 8. The method of claim 1wherein forming the bag comprises cutting the length of film and the bagclosure strip to selected lengths after the bag closure strip isattached, and sealing cut ends of the film and closure strip to form thesealed edges of the bag.
 9. The method of claim 1 further comprisingfilling the bag with a quantity of contents; and forming a seal alongthe open end of the filled bag along the closure strip, with the flapforming an expandable gusset of the filled bag.
 10. A method of fillingand sealing a reclosable bag, the method comprising providing a bagcomprising a body having an open end, two opposing, broad face panelsdefining a volume therebetween for holding a quantity of contents, and aflap attached to one of the broad face panels along the open end, theflap having an inwardly-facing fold for forming an expandable gussetbetween the broad face panels after the open end is sealed; and areclosable bag closure secured to a free edge of the flap and having anexposed side defining one side of a fill opening at the open end of thebag; filling the bag with contents through the fill opening; and sealingthe exposed side of the closure strip to the other of the broad facepanels of the bag, to permanently close the fill opening.
 11. A methodof vertically forming, filling and sealing recloseable bags, the methodcomprising attaching a bag closure strip along one longitudinal edge ofa length of bag film; forming from the length of bag film a bag having,two broad, opposing faces and an expandable gusset between the broadfaces adjacent the closure strip; filling the bag with a quantity ofcontents; and forming a seal along an edge of the bag between the broadfaces and crossing the closure strip at one end of the expandablegusset, to seal the filled bag.